One of the more reliable means to prevent screws from loosening is to use "Double nut" method. There are some fundamental points that must be understood regarding this method. [Fig.1] and [Fig.2] are the fundamental rules with double nutting. If these rules are not observed, seemingly reliable implementation will not yield effective results.

Fundamentals of loosening prevention double nut method

1. Effective when the screws may come loose due to rotational force caused by vibrations
2. Not effective for loosening caused by material elongation due to material properties.
3. Proper procedure is required for double nut tightning. (See [Fig.1])
4. The strength of double nut method depends on the strength of the nuts used (principle). Thickness of the two nuts used must be carefully considered.